In “Jealous Guy,” John Lennon described his heart-aching insecurity as “shivering inside.” In “The Rain Song,” Led Zeppelin’s Robert Plant bemoaned, “I’ve felt the coldness of my winter.” And in “It Will Be Lonely This Christmas,” the ’70s band Mud crooned desperately, “It’ll be cold, so cold, without you to hold.”

The poets were right about the chill of isolation and rejection — more, perhaps, than even they knew: when a person feels lonely or is being excluded by others, his or her skin literally becomes colder.

For the past several years, our lab has been studying just how people respond to exclusion and other social interactions. In one recent experiment, published earlier this year in the journal Acta Psychologica, we asked dozens of students to participate in a simulated ball-tossing game with computer-generated cartoonlike figures called avatars.

Research by the Purdue University psychologist Kip Williams, who programs these avatars to refrain from tossing the ball to certain human subjects, has shown that people feel bad when left out. But perhaps more striking is what happens to a person’s body temperature in such scenarios.